As an eerie silence falls over downtown Boston in the wake of the twin bombings, security and solidarity remains heightened across the nation.

The unfinished meals of fleeing customers rest on tables on April 16 at an outdoor restaurant that was evacuated after a pair of bombs were detonated near the finish line of the Boston Marathon, killing three people and hospitalizing at least 176.

Although no suspects or motives have been identified, the ongoing FBI investigation has confirmed the twin bombings as an act of terrorism.

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Photo: Spencer Platt/Getty Images

Unclaimed finish line goody bags rest on the ground in the early morning of April 16 near the scene of the Boston Marathon bombing.

Messages of support and love are projected on the side of the Peter Jay Sharp building in the evening following the bombings at the Brooklyn Academy of Music. The last minute installation was created by the NYC Light Brigade and The Illuminator, a political art project born out of the Occupy Wall Street movement.

The city lights of Boston are seen in this photo captured from the International Space Station on April 16 by NASA Commander Chris Hadfield.

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Photo: Andy Lyons/Getty Images

A baseball glove belonging to Ben Revere of the Philadelphia Phillies is taped with a message ('Pray for Boston') in memorial of the tragedy in Boston on April 15 during a game against the Cincinnati Reds at Great American Ball Park in Cincinnati, Ohio.

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Photo: Spencer Platt/Getty Images

Debris and litter are strewn about an empty street on April 16, hours after the downtown area was evacuated due to the Boston Marathon bombings.

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Photo: Spencer Platt/Getty Images

Unused thermal blankets for marathon participants are piled near the scene of the twin bombing on April 16 in downtown Boston.